Dual locking construction for paperboard wrappers



DUAL LOCKING CONSTRUCTION FOR PAPERBOARD WRAPPERS Filed Nov. 14, 1957 Feb. 28, 1961 o. w. STONE ET AL 3 Sheets-Sheet 1 HEQD.

INVENTOR. ORISON W. STONE LAURIE H. CAMPBELL ATTORNEYS.

Feb. 28, 1961 Q STONE ET AL 2,973,129

DUAL LOCKING CONSTRUCTION FOR PAPERBOARD WRAPPERS Filed Nov. 14, 1957 s Sheets-Sheet 2 W. STONE LAURIE H. CAMPBELL AfTOR/VEKS Feb. 28,1961 0. w. STONE ET AL 2,973,129

DUAL LOCKING CONSTRUCTION FOR PAPERBOARD WRAPPERS Filed Nov. 14, 1957 :s Sheets-Sheet s Q Q 5* 1; n 9 9 11 IS V M la I I8 lfi l law Is I? IQ Qi-l? I8 QB 1; I 1; 188 gm 10 s e a lo INVENTOR. ORISON W. STONE LAURIE H. CAMPBELL- United States PatentfC) DUAL LOCKING CONSTRUCTION FOR PAPERBOARD WRAPPERS Orison W. Stone, Valley Cottage, N.Y., and Laurie H.

Campbell, New London, Conn., assignors to Contin'ental Can Company, Inc., New York, N.Y., a corporation of New York Filed Nov. 14, 1957, Ser. No. 696,365

1 Claim. (Cl. 229-16) The invention relates to an improved locking construction for a paperboard wrapper. It has special application to wrap-around cartons or carriers for canned goods as used, for example, in retail packaging of cans of beer and foods in lots of two, three, six or more cans.

Such wrap-around cartons or carriers are made from rectangular blanks folded into the form of a rectangular tube and having edges overlapped at one side of the tube. These overlapped edges may be glued together so as to hold the paperboard wrapper tightly around the cans, and when this is done the resulting package is quite strong and will meet high standards of acceptability. Also the package can be made tight enough that, when provided with typical slotted fold lines or other customary retaining means, the cans will be held effectively against dropping out of the open ends of the Wrapper. Sometimes, however, it is considered desirable to have a wrapper which does not have to be glued together. In such instances, it has been a common expedient to use interlocking tongues and slots in the overlapping edges of wrapper. But this does not make a very strong package, nor one which can be relied on to remain as tight as a glued wrapper. An object of our invention is to provide an improved locking construction which will more nearly compare with a glued wrapper in respect to strength, tightness and resistance to stresses tending to tear the wrapper open at its overlapped edges.

According to our invention the wrapper is made with what may best be described as a dual locking construction including: (1) a first locking means comprising interlocking tongues and slots in the overlapped edges of the wrapper, and (2) a second locking means comprising locking end flaps folded into overlapping relation at the corners of the wrapper and having interlocking tongues and slots in the corner overlaps. We have found that these two locking means coact one with the other in resisting stresses tending to tear the wrapper open at its overlapped edges.

With reference to the drawings we shall now describe the best mode contemplated by us for carrying out our invention.

Fig. 1 is a bottom perspective view of a paperboard wrapper including our dual locking construction.

Fig. 2 is a schematic view representing the end of such a wrapper and showing how lateral tearing stresses on the first locking means are resisted also by the second locking means.

Fig. 3 is a similar schematic view showing how downward load stresses on the first locking means are resisted also by the second locking means.

Fig. 4 is a plan view of the paperboard blank from which the wrapper of Fig. l is formed.

In Fig. l, we show how our invention is applied to a paperboard wrapper 4 having the general form of a foursided tube made from a rectangular blank having edges 5 and 6 overlapped at one side, 7, of the tube. Our dual locking construction includes a first locking means com- 2,973,129 Patented Feb. 2 8, 1961 prising interlocking tongues and slots, 8 and 9, respectively, and 10 and 11, respectively. These tongues and slots may be of any well known construction and they therefore need not be described in detail. However, they should be of the type wherein the tongues have projections which engage the slots firmly to prevent the tongues from pulling out once they have been pushed through the slots to make the lock. The locking con'structionfurther includes a second locking means comprising locking end flaps 12 to 16, inclusive, folded into overlapping relation at the corners of the wrapper and having interlocking tongues and slots 17 and 18, respectively, in the corner overlaps. The end flaps 12 to 16 may be considered to have afunction as a partial end closure for the wrapper, but we recognize that such partial end flaps have been known heretofore. What weare primarily concerned with here is the problem of how to reinforce an unglued wrapper so that its overlapping edges, when held together only by little interlocking tongues or tabs, can be kept from tearing apart. We achieve this reinforcing function by using flaps overlapping and interlocked at the corners of the wrapper.

The value of this reinforcing function will be appreciated from a study of the schematic views, Figs. 2 and 3. Here for simplicity we use an abstract form to represent the first and second locking means. The first is represented at 8, 9', the second at 17. Referring to Fig. 2, consider first the lateral stresses tending to pull the wrapper open at its sides. Taking the hypothetical case where such stresses are sufl'iciently great to tear open the package, we may represent this hypothetical condition by the dot dash lines. Notice that the tongues and slots 8', 9 have been pulled apart as represented at 8", 9", and that the second locking means have also been pulled apart as represented by the tongues 17' and slots 18". Therefore the two locking means coact one with the other in resisting the lateral stresses tending to tear the wrapper open at its overlapped edges. Similarly, in Fig. 3, we consider the results of over limit stresses imposed by a load acting downwardly against the bottom of the wrapperas when the wrapper has a handle on the top (not shown) and is being used as a carrier. The relative displacements of the locking components 8", 9" and 17, 18", explain how the two locking means coact with one another in resisting such downward loading stresses. These theoretical analyses are offered merely in an attempt to aid others in appreciating the nature of our dual locking construction, and we do not wish to be bound by any particular theory of its operation or as to why it is so effective for the purposes stated.

The terms and expressions which we have employed are used in a descriptive and not a limiting sense, and we have no intention of excluding such equivalents of the invention described, or of portions thereof, as fall within the scope of the claim.

We claim:

Dual locking construction for a paperboard wrapper having the general form of a four-sided tube made from a rectangular blank having edges overlapped at one side of the tube, said dual locking construction including: a first locking means comprising interlocking tongues and slots in said overlapped edges, said tongues folded about locking edges of the slots arranged substantially parallel to the axis of the tube, and a second locking means comprising partial end fiaps folded into overlapping relation at the corners of the wrapper to form an inwardly projecting marginal flange extending around the ends of the tube, said end flaps having interlocking tongues and slots in the four corners of said marginal flange, said lastnamed tongues folded about locking edges of the slots with which they interlock, said locking edges disposed References Cited in the file, of this patent UNITED STATES PATENTS Blandford Feb. 3, 1925 4 Kretchmer July 6, 1943 Cohen et al Oct. 31, 1944 Acker Oct. 31, 1950 Keller Nov. 10, 1953 Seith May 17, 1955 Gentry Mar. 26, 1957 

